Apparatus for cleaning granular material



May 5, 1953 R. WEBSTER 2,637,330

APPARATUS FOR CLEANING GRANULAR MATERIAL Filed Dec. 20, 1946 Patented May 5, 1953 UNITED STATES PATENT OFFICE APPARATUS FOR CLEANING GRANULAR.

MATERIAL Roderickv Webster, Chicago, Ill-.,;assignorto The Hydro-Blast Corporation, Chicago,v 111., acorporation of Illinois 3 Claims.

This invention relates to apparatus for cleaning granular material and more particularly to apparatus for scrubbing sand such as used foundry sand to clean it for reuse.

' Heretolore in reconditioning used foundry sand and particularly core sand it has been the usual practice to mix the sand with water to form a flowable mixture containing approximately at least thirty (30%) per cent water. serves both to wash free foreign material from the sand and to facilitate handling of'the sand by enabling it to be pumped. Before scrubbing to remove foreign material adhering to the sand grains it has been necessary to dewater the mixture to reduce its water content to about twenty (20%) per cent in order that the sand grains can properly be scrubbed. This dewatering operation requires a large amount of equipment occupying a large floor space and contributing substantially to the cost of a sand treating installation.

It is one of the objects of the present invention to provide apparatus for cleaning granular material in whlch'a flowable mixture of granular material and water can be scrubbed without requiring dewatering.

Another object is to. provide apparatus for cleaning granular material in which a flowable mixture of the material and. water is scrubbed in a continuous process.

Still another object is to provide apparatus in which the parts subjected to maximum wear are easilyaccessible for repair or replacement.

A further object is to. provide apparatus for cleaning granular material which has maximum capacity for minimum size and which will occupy a relatively small floor space.

The above and other objects and advantages of the invention will be more readily apparent from the following description when read in connection with the accompanying drawing, in which- Figure l is a side elevation of an apparatus embodying the invention;

Figure 2' is a horizontal sectionon the line.2-2 (if-Figure l; and

Figure 3 is a partial enlarged section on the line 3--3 of Figure 1.

The apparatus as shown comprises a vertical open topped container l0 which is preferably a Q cylindrical tank with its axis vertical. The container may be supported in any desired elevation on a framework H and may be permanently installed in place to form a part of a sand treating system.

The water its opposite surfaces.

Thecontainer receives-a fiowable mixture of sand and water or-of other granular material to be cleaned through an inlet'trough l2 which as shown discharges into the upper open end of the container adjacent one side thereof. The treated material leaves the container through an outlet opening formed in one-wall thereof adjacent the top and which connects to an outlet trough l3 discharging the treated mixture to anyadditional desired apparatus for further treatment.

The mixture in the receptacle is adapted to be agitated and causedto now by air-impeller which as shown comprisesa circular blade l5 having outwardly; extending curved ribs or vanes it on The impeller is supported by-a driving shaft 16 which extends axially down into the container to-supportthe impeller in the central lower part of the container below the vertical center thereof but spaced slightly above the containerbottom.

As the impellerrotates. it will cause the mixture to be thrown out radially due to the action of thevanes l5 thereon to set up currents tending to rise at the sides of the container above the impeller and to return to the impeller in the central part of the container. An additional circulation will beset up below the impeller level downward along the sides of the container and upward to the impeller in the central part of the container". During this circulation the sand grains suspended in the liquid are scrubbed against the impeller vanes and against each other so that adhering foreign material will be loosened therefrom. The circulation also maintains the sand grains and the foreign material in suspenslon in theliquid so that asfresh mixture is continuously added the mixture overflowing through the outlet trough will contain both water and suspended solid particles.

To prevent themixture from passing directly out of the container without adequate scrubbing, walls or-bafiies are provided around-the outlet opening. As shown, there are two Vertical walls orbafiles indicated at I! which extend from the bottom of the container to a level slightly above the level of the outlet opening and which lie closely adjacent-the opposite sides of the outlet opening; These" walls or baffles serve to break up the rotary circulation of the mixture causing an increased agitation thereof and further preventing the mixture'from flowing directly out the outlet opening without sufficient circulation to produce proper scrubbing. In operation there will tend to be a vertical circulation between the spaced walls I! which might carry unscrubbed particles through the outlet opening and to prevent this a wall or bafile I8 is provided extending radially inward from the container wall between the vertical baflies I! at a level below the outlet opening and above the impeller. In the preferred construction, as shown, the wall 18 slopes upwardly to terminate substantially level with the outlet opening and provides an open topped pocket around the outlet opening from which relatively quiet mixture can flow. I have found, however, that a horizontal baffle spaced slightly below the outlet opening level will function substantially as well. This construction prevents a direct fiow of rapidly moving mixture through the outlet opening and insures that the mixture will be retained in the receptacle a sufficient time so that it will be properly scrubbed.

The only part of the apparatus which is subjected to any substantial amount of wear is the impeller itself which has been found to wear relatively quickly. However, the impeller is an extremely simple and inexpensive unit so that it can be replaced periodically without substantially increasing the cost of the cleaning operation.

To provide easy access to the impeller for removal and replacement thereof, the shaft 16 may be directly connected to a driving motor 2! which is supported on a carriage 22. The carriage is slidable vertically on vertical supporting pipes or tubes 23 which extend beside the receptacle. Preferably, the carriage is connected to one end of a cord 2 which runs over a pulley 25 at the top of the tubes and is connected at its opposite end to a counter-balance weight 26. In this way the carriage can be moved vertically on the tubes with a minimum of eifort to raise the motor and shaft sufiiciently so that the impeller will lie either closely adjacent or slightly above the top of the receptacle for easy access thereto. Upon replacement of a defective impeller the carriage can be slid downwardly to bring the parts substantially to the position shown in Figure 1 for operation.

I have found that a very effective scrubbing operation can be performed on fiowable mix-v tures of granular material such as sand in the apparatus of the invention and that the operation can be carried on continuously. That is, during operation mixture to be cleaned can be flowed continuously into the receptacle through the inlet trough I2 and cleaned mixture can be continuously withdrawn through the outlet opening. It will be understood that for foundry use the cleaned mixture may be subjected to a classifying operation to remove the small and light foreign particles from the desirable sand grains and that the sand may thereafter be dried.

While one embodiment of the invention has been shown and described in detail herein, it will be understood that this is illustrative only and is not to be taken as a definition of the scope of the invention, reference being had for that purpose to the appended claims.

What is claimed is:

1. Apparatus for cleaning granular material comprising a vertical substantially cylindrical receptacle, means to supply a flowable mixture of granular material and water to the receptacle, an impeller in the lower central part of the receptacle to force the mixture radially outward,

means forming an outlet opening in the side of the receptacle adjacent its top and constituting the sole outlet for cleaned material, vertical walls in the receptacle closely adjacent to the sides of the outlet opening extending radially inward therefrom, and a wall extending inward from the receptacle side well below the outlet opening and between said vertical walls and joined to the vertical walls and to the receptacle wall along a. continuous horizontal line between the vertical walls to prevent upflow of mixture between the vertical walls to the outlet opening.

2. Apparatus for cleaning granular material comprising a vertical substantially cylindrical receptacle, means to supply a flowable mixture of granular material and water to the receptacle. an impeller in the lower central part of the receptacle to force the mixture radially outward,

means forming an outlet opening in the side of the receptacle adjacent its top and constituting the sole outlet for cleaned material, vertical walls extending upward from the bottom of the receptacle to a level above the outlet opening closely adjacent to the sides of the outlet opening and extending radially inward therefrom, and a wall extending inward from the receptacle side wall between the vertical walls at a level between the impeller and the outlet opening, the last named wall joining the receptacle side wall along a continuous horizontal line between the vertical walls and joining the vertical walls.

3. Apparatus for cleaning granular material comprising a vertical substantially cylindrical receptacle, means to supply a flowable mixture of granular material and water to the receptacle, an impeller rotatably mounted on a vertical axis in the lower central part of the receptacle to circulate the mixture radially outward therefrom, the receptacle being formed in its side adjacent its top with an outlet opening constituting the sole outlet for cleaned material, a vertically elongated baii'le extending radially inward from the receptacle wall closure adjacent at least one side of the opening, and a second bafiie extending inward and upwardly at an acute angle to the vertical from and connected throughout its width to the receptacle side wall adjacent to and below the opening, the second bailie joining the first named bafiie and being substantially coextensive radially therewith.

RODERICK WEBSTER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 489,797 Faber Jan. 10, 1893 711,470 Caswell Oct. 21, 1902 1,335,912 Olson Apr. 6, 1920 1,861,163 Ray et a1 May 31, 1932 1,967,028 Howe July 17, 1934 1,984,431 Robertson Dec. 18, 1934 2,000,418 Ruth May 7, 1935 2,104,456 Friedman Jan. 4, 1938 2,122,217 Sisson June 28, 1938 2,297,009 Mead et a1 Sept. 29, 1942 2,461,746 Lathrop et al. Feb. 15, 1949 2,477,948 Allen Aug. 2, 1949 I FOREIGN PATENTS Number Country Date Australia May 2, 1940 

